Basestation Transmitter System Design

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Basestation Transmitter System Design

• Johan Vanderhaegen
• Robert Brodersen
• University of California, Berkeley
• Januari 2000

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Transmitter blockdiagram
pulse shaping filter
smoothing filter
PA
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Transmitter Design

• Ideal transmitter specifications
• Baseband equivalent model
• Infinite wordlength in digital filter
• Linear, noiseless analog front-end
• Non-idealities
• Truncation noise of digital filter
• Impairments of analog font-end

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Ideal Transmitter

• Input discrete time symbol stream
• Output continuous time signal

• digital filter DAC analog filter

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PSD After DAC
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Practical Digital Filter

• Finite filter length
• Coefficient quantization
• Finite wordlength
• Two requirements
• Maximum out-of-band spurious response
• Minimum SNR

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Quantized Coefficients
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Modeling Issues

• High level model only pulse shaping filter
• Low level model
• Fixed point model for pulse shaping filter
• Overall nonlinearity for entire analog front-end
• Stochastic models for DAC nonlinearity, I/Q
  mismatch
• Phase noise